QMP does not load all plug-ins on startup, instead it will attempt to load plug-ins only when most opportune in order to speed-up load-time of the application. The following are the usual cases for when certain plug-in types will be loaded:

1. Always on startup
   • Library plug-in are loaded on startup to facilitate metadata lookup for any tracks loaded on startup, and for any UI initialization.
   • DSP plug-ins are loaded on startup due to many of this type having some UI that is expected to appear on startup.
   • General plug-ins are also loaded on startup due to many of this type having some UI that is expected to appear on startup.
2. Plug-in requested on startup
   • Input and Source plug-ins can request to be loaded at startup on an individual basis. See Initialization for info on how to set this.
3. On demand
   • All other plug-in types are loaded 'on demand'. That is, they are only loaded at the moment when they are called by the player.

The Plug-in Cache is a file that contains basic information about all DLLs located in QMP's plug-in folder. This cache helps QMP determine which DLL are actual plug-ins and of what type. It also contains some initialization information such as the display name for the plug-in. This allows QMP to 'virtually load' plug-ins without actually physically loading them in to memory and initializing them. The benefit is a quicker startup and initialization time for QMP. Any plug-in that is 'virtually loaded' will be physically loaded and initialized only when is about to be called by the player.